الفهرس 
Title : A study on thermal and electrical stresses of power transformers
SummaryOnly 14 pages are availabe for public view
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Abstract
Power transformers are intended to withstand system abnormalities such as over voltages and overloads. Diagnostics and monitoring of transformer are the effective methods to prevent failures and ensure the network reliability. The solid insulation of power transformers is a function of time which depends on the temperature, moisture amount, acids and oxygen in the insulation system. This thesis focuses on thermal and electrical stresses that affect the insulation of power transformer and hence cause aging of power transformer. IEEE loading guide and IEC 60354 equations were modeled and thermal model is studied to estimate transformer top oil and hotspot temperature. Transient overvoltage is studied also to show how the power transformer can be exposed to electrical stresses causing insulation overheating. Remaining service life of the transformer is estimated through degree of polymerization of paper (DP) insulation